Button cover



FIG. 1 is a front perspective view of a button cover;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a top elevation view thereof;

FIG. 4 is a back elevation view thereof;

FIG. 5 is a bottom elevation view thereof; and,

FIG. 6 is a left side elevation view thereof, a right side elevation view being a mirror of the left side.

The broken lines form no part of the claimed design. 

CLAIM The ornamental design for a button cover, as shown and described. 